Mechanics

WHEN IT RAINS AND WHEN ITS FIRST STARTED IN THE MORNING UP UNTIL IT REACHES PEAK ENGINE TEMP IT MISFIRES WHAT COULD BE THE PROBLEM

1999 GMC Sierra • 265,000 miles

The truck has a 4.3 vortec in it
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DerrickG6687
November 22, 2011.



http://www.2carpros.com/articles/engine-misfires-or-runs-rough

1.Defective spark plugs

2.Inadequate spark/coil,defective spark plug wire.

3.Lack of compression

4.False air leakage.

5.Faulty fuel injectors.

6.Insufficient fuel pressure.

7.Contaminated fuel.

8.EGR valve that is leaking.

9.Oxygen sensors.

10.Throttle position sensor.

11.Manifold absolute pressure sensor

12.Mass Airflow Sensor

13.Idle air control valve

Note: If it doesn't apply disregard it-

Rasmataz
Nov 22, 2011.